Evidence for an Unprecedented Histidine Hydroxyl Modification on D2-His336 in Photosystem II of Thermosynechoccocus vulcanus and Thermosynechoccocus elongatus

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• 作者：Miwa Sugiura ; Kazumi Koyama ; Yasufumi Umena ; Keisuke Kawakami ; Jian-Ren Shen ; Nobuo Kamiya ; Alain Boussac
• 刊名：Biochemistry
• 出版年：2013
• 出版时间：December 31, 2013
• 年：2013
• 卷：52
• 期：52
• 页码：9426-9431
• 全文大小：346K
• ISSN：1520-4995

文摘

The electron density map of the 3D crystal of Photosystem II from Thermosynechococcus vulcanus with a 1.9 脜 resolution (PDB: 3ARC) exhibits, in the two monomers in the asymmetric unit cell, an, until now, unidentified and uninterpreted strong difference in electron density centered at a distance of around 1.5 脜 from the nitrogen N未 of the imidazole ring of D2-His336. By MALDI-TOF/MS upon tryptic digestion, it is shown that 20鈥?0% of the fragments containing the D2-His336 residue of Photosystem II from both Thermosynechococcus vulcanus and Thermosynechococcus elongatus bear an extra mass of +16 Da. Such an extra mass likely corresponds to an unprecedented post-translational or chemical hydroxyl modification of histidine.